struts配置result类型为json后导致页面不能访问的错误

错误提示为：

Caused by: There is no result type defined for type 'json' mapped with name 'success'.  Did you mean 'json'? - result

解决办法。将package包的继承改为json-default即可，如：   <package name="jsontest" extends="json-default">